Biology Unit 2

Front 1

nucleus

Back 1

center of the atom which contains protons & neutrons

Front 2

compound

Back 2

formed by the chemical combination of two or more elements

Front 3

proton

Back 3

positive charge found in nucleus

Front 4

electron

Back 4

negative charge found in energy levels

Front 5

neutron

Back 5

particle found in the nucleus with a neutral charge

Front 6

atoms

Back 6

basic unit of matter

Front 7

element

Back 7

pure substance composed of only one type of atom

Front 8

covalent bond

Back 8

formed when electrons are shared between atoms

Front 9

isotopes

Back 9

atoms of the same element that have different numbers of neutrons

Front 10

ionic bond

Back 10

the bond between positive and negative ions formed when one or more electrons are transferred from one atom to another

Front 11

electron cloud

Back 11

space around the nucleus occupied by electrons

Front 12

ion

Back 12

positively or negatively charged atom formed by gaining or losing of electrons

Front 13

van der Waals forces

Back 13

slight attraction of oppositely charged particles

Front 14

molecule

Back 14

smallest unit of a covalent compound

Front 15

cohesion

Back 15

attractions between molecules of the same substances

Front 16

polar molecule

Back 16

molecule with an unequal distribution of electrons resulting in a positive and negative poles

Front 17

pH scale

Back 17

scale from 0-14 that measures the amount of hydrogen ions in a solution-the more hydrogen ions the lower the pH

Front 18

acid

Back 18

solution that contains a higher concentration of hydroxide ions than hydrogen ions (0-6.9 on pH scale)

Front 19

base

Back 19

solution that contains a higher concentration of hydroxide ions than hydrogen ions (7.1-14 on pH scale)

Front 20

solvent

Back 20

substance in which the solute is dissolved

Front 21

solute

Back 21

substance that is dissolved by a solvent

Front 22

solution

Back 22

type of mixture in which two or more substances are evenly distributed (homogeneous mixture)

Front 23

buffers

Back 23

weak acids or bases that can react with strong acids or bases to prevent sharp changes in pH

Front 24

products

Back 24

elements or compounds that are produced by a chemical reaction

Front 25

chemical reaction

Back 25

process that changes one set of chemicals into another set of chemicals

Front 26

reactants

Back 26

elements or compounds that enter into a chemical reaction

Front 27

enzymes

Back 27

proteins that act as biological catalysts

Front 28

catalyst

Back 28

substance that speeds up the rate of a chemical reaction by lowering the activation energy.

Front 29

alpha (a) helix

Back 29

A spiral shape; one form of the secondary structure of proteins

Front 30

amino acid

Back 30

An organic molecule possessing both carboxyl and amino groups. They serve as the monomers of polypeptides.

Front 31

atherosclerosis

Back 31

A cardiovascular disease in which fatty deposits called plaques develop in the inner walls of the arteries

Front 32

beta (ß) pleated sheet

Back 32

One form of the secondary structure of proteins in which the polypeptide chain folds back and forth. Two regions of the chain lie parallel to each other and are held together by hydrogen bonds.

Front 33

carbohydrate

Back 33

A sugar (monosaccharide) or one of its dimers (disaccharides) or polymers (polysaccharides) having one carbon for every two hydrogens and one oxygen.

Front 34

catalyst

Back 34

A chemical agent that increases the rate of a reaction without being consumed by the reaction.

Front 35

cellulose

Back 35

A structural polysaccharide of plant cell walls

Front 36

cholesterol

Back 36

A steroid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids

Front 37

dehydration (condensation) reaction

Back 37

A reaction in which two molecules become covalently bonded to each other through the loss of a small molecule

Front 38

deoxyribonucleic acid (DNA)

Back 38

A double-stranded nucleic acid containing deoxyribose and the bases adenine, guanine, cytosine, and thymine.

Front 39

deoxyribose

Back 39

The sugar component of DNA nucleotides

Front 40

disaccharide

Back 40

A double sugar

Front 41

disulfide bridge

Back 41

A strong covalent bond formed when the sulfur of one cysteine monomer bonds to the sulfur of another cysteine monomer.

Front 42

double helix

Back 42

The double-stranded form of DNA

Front 43

enzyme

Back 43

A macromolecule serving as a catalyst

Front 44

fat

Back 44

A lipid consisting of three fatty acids linked to one glycerol molecule; called a triglyceride.

Front 45

fatty acid

Back 45

A long hydrocarbon chain carboxylic acid. They vary in length and in the number and location of double bonds; three linked to a glycerol molecule form a fat molecule (triglyceride).

Front 46

gene

Back 46

A single unit of hereditary information (one section of DNA) that codes for one polypeptide.

Front 47

hydrolysis

Back 47

A chemical process that lyses (breaks) the bond between two monomers by adding water to them.

Front 48

lipids

Back 48

A group of hydrophobic (non-polar) molecules including triglycerides (fats), phospholipids, steroids, and waxes.

Front 49

monomer

Back 49

The subunit that serves as the building block of a polymer.

Front 50

monosaccharide

Back 50

The simplest carbohydrate

Front 51

nucleic acid

Back 51

A polymer (polynucleotide) consisting of many nucleotide monomers (e.g. DNA and RNA)

Front 52

nucleotide

Back 52

The building block of a nucleic acid

Front 53

peptide bond

Back 53

The covalent bond between the carboxyl group on one amino acid and the amino group on another

Front 54

phospholipid

Back 54

A lipid made up of glycerol joined to two fatty acids and a phosphate group. The hydrocarbon are hydrophobic and the phosphate heads are hydrophilic.

Front 55

polymer

Back 55

A long molecule consisting of many similar or identical monomers linked together.

Front 56

polynucleotide

Back 56

A polymer consisting of many nucleotide monomers in a chain; nucleotides can be those of DNA or RNA.

Front 57

polypeptide

Back 57

A polymer (chain) of many amino acids linked together by peptide bonds.

Front 58

polysaccharide

Back 58

A polymer of many monosaccharides

Front 59

primary structure

Back 59

The level of protein structure referring to the specific sequence of amino acids.

Front 60

protein

Back 60

A functional biological molecule consisting of one or more polypeptides folded and coiled into a specific three-dimensional structure.

Front 61

quaternary structure

Back 61

The three dimensional arrangement of multiple polypeptide sub-units into one protein

Front 62

ribonucleic acid (RNA)

Back 62

A type of nucleic acid consisting of nucleotide monomers with a ribose sugar and the nitrogenous bases uracil (U), adenine (A), cytosine (C), and guanine (G)

Front 63

ribose

Back 63

The sugar component of RNA nucleotides.

Front 64

saturated fatty acid

Back 64

A fatty acid in which all carbons in the hydrocarbon tail are connected by single bonds

Front 65

secondary structure

Back 65

The localized coils and folds in the polypeptide chain (alpha helixes and beta sheets)

Front 66

starch

Back 66

A storage polysaccharide in plants

Front 67

steroid

Back 67

a type of lipid characterized by a carbon skeleton consisting of four rings with various chemical groups attached (modified cholesterol).

Front 68

tertiary structure

Back 68

Three dimensional arrangement of a polypeptide determined by interactions among various side chains (R groups)

Front 69

trans fat

Back 69

An unsaturated fat containing one or more trans double bonds.

Front 70

unsaturated fatty acid

Back 70

A fatty acid possessing one or more double bonds between the carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.